Number of Quarts in a Gallon

1 gallon is equal to 4 quarts. This applies to both the US customary units as well as UK imperial units of measurement, as long as it is consistently used (in example, 1 US gallon = 4 US quarts). Consistency with the use of dry and liquid measures (for example, 1 dry US gallon = 4 dry US quarts) is also implicit in this calculation.